In this module, you will learn:

  • the definition of work done
  • how to calculate work done

Resources to help you:

  • Textbook: page 122 and 123

Work Done

Work is done when an object moves while a force is being exerted on it.


Work done is measured in the unit of joule (J) or newton metre (Nm). Joule is the SI unit of work done.

When the pulling force moves the box, work is done.

Credit: @iimage via YayImages (edited)

Work is done if the three conditions apply

  1. There is a force acting on an object.
  2. ​The object moves.
  3. ​The movement of the object is in the same direction of the force.

Calculating Work Done


work done = Force x distance moved in direction of the force


where Force is measured in newtons (N) and distance in metre (m)

​If distance is in not in m (e.g. cm or mm), it has to be converted to metre first.

Watch the video

See how to use the formula to calculate Work Done

Source: https://www.youtube.com/watch?v=JHEmPZ-YnrU

You can change the speed to 0.75x to make it easier to listen.

A little note on doing your working

In Science, we are only looking for very simple working and not the calculation itself as you are allowed to use a calculator.

Step 1: Write the formula, w = F x d

Step 2: Substitute the value for force (F) in newtons and distance (d) in metres (same direction as the force)

Step 3: Use a calculator to do the calculation

Step 4: Write the answer with the unit

e.g. w = f x d

= 50 N x 5 m

= 250 J

That is really you really need to write as your working.

Working if distance is not in metre

If the distance is not in metre, you will have to convert it.

1 m = 100 cm

1 m = 1000 mm


For example,

Calculate work: A 100 Newton force is applied to move an object a distance of 500 centimetres across the floor?


First change the 500 centimetres into metre.

1 m = 100 cm

500 cm = 500 / 100

= 5 m


w = F x d

= 100 N x 5 m

= 500 J

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